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Python server implementation on top of Tornado framework


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Unfortunately, Socket.IO 0.8 branch is abandoned, there are huge amount of bugs and nothing getting fixed. I would suggest to look at alternative options, for example SockJS <>. There's sockjs-tornado <> too. I don't plan to support TornadIO2 anymore, assuming that parent library is no longer maintained.

If you still want to try Socket.IO 0.8.x with Python, TornadIO2 is quite stable and used in production.



This is python server implementation of the Socket.IO realtime transport library on top of the Tornado framework.

TornadIO2 is compatible with 0.7+ version of the Socket.IO and implements most of the features found in original Socket.IO server software.

Key features:

  • Supports Socket.IO 0.8 protocol and related features
  • Full unicode support
  • Support for generator-based asynchronous code (tornado.gen API)
  • Statistics capture (packets per second, etc)

What is Socket.IO?

Socket.IO aims to make realtime apps possible in every browser and mobile device, blurring the differences between the different transport mechanisms. It's care-free realtime 100% in JavaScript.

You can use it to build push service, games, etc. Socket.IO will adapt to the clients browser and will use most effective transport protocol available.

Getting Started

In order to start working with the TornadIO2 library, you have to have some basic Tornado knowledge. If you don't know how to use it, please read Tornado tutorial, which can be found here.

If you're familiar with Tornado, do following to add support for Socket.IO to your application:

  1. Derive from tornadio2.SocketConnection class and override on_message method (on_open/on_close are optional):

    class MyConnection(tornadio2.SocketConnection):
        def on_message(self, message):
  2. Create TornadIO2 server for your connection:

    MyRouter = tornadio2.TornadioRouter(MyConnection)
  3. Add your handler routes to the Tornado application:

    application = tornado.web.Application(
        socket_io_port = 8000)
  4. Start your application
  5. You have your server running at port 8000. Simple, right?

Starting Up

We provide customized version (shamelessly borrowed from the SocketTornad.IO library) of the HttpServer, which simplifies start of your TornadIO server.

To start it, do following (assuming you created application object before):

if __name__ == "__main__":
    socketio_server = SocketServer(application)

SocketServer will automatically start Flash policy server, if required.

If you don't want to start IOLoop immediately, pass auto_start = False as one of the constructor options and then manually start IOLoop.

More information

For more information, check TornadIO2 documentation and sample applications.



Ping sample which shows how to use events to work in request-response mode. It is in the examples/ackping directory.

Cross site

Chat sample which demonstrates how cross-site communication works (chat server is running on port 8002, while HTTP server runs on port 8001). It is in the examples/crosssite directory.

Events and generator-based async API

Example which shows how to use events and generator-based API to work with asynchronous code. It is in the examples/gen directory.


Ping and chat demo running through one connection. You can see it in examples/multiplexed directory.


TornadIO2 collects some counters that you can use to troubleshoot your application performance. Example in examples/stats directory gives an idea how you can use these stats to plot realtime graph.

RPC ping

Ping which works through events. It is in the examples/rpcping directory.


Simple ping/pong example with chat-like interface with selectable transports. It is in the examples/transports directory.


Python server implementation on top of Tornado framework







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